1. Field of the Invention
The present invention relates to an ink jet recording apparatus which performs recording by discharging ink on a recording medium from a recording head.
2. Related Background Art
In an ink jet recording apparatus which performs recording by discharging ink from a recording head on a recording medium such as a recording sheet, recording is performed by discharging the ink from a minute discharge port. Hence, a discharge failure resulting from thickening and fixing of ink due to evaporation of ink near a discharge port, adhesion of ink and foreign particles, such as paper powder, to a discharge port surface, and the like may arise. Hence, in an ink jet recording apparatus, by providing a recovery mechanism portion and performing a recovery action at predetermined intervals, ink discharging performance is maintained and recovered.
The recovery mechanism portion is for maintaining and recovering recording quality in a normal state by resolving a clogging and the like of a recording head which discharges ink and performs recording. This recovery mechanism portion comprises pumping means for sucking ink from a discharge port, capping means of making a cap abut and cover the discharge port, and wiping means of making a wiper rub a discharge port surface and wipe it. As conventional structure of this recovery mechanism portion, what is proposed is a structure that a slider which is movable only in a predetermined range and interlocking with a motion of a carriage mounting a recording head is provided, and a cap and a wiper are mounted in this slider.
FIG. 10 is a perspective view showing a recovery mechanism portion which is constructed of a slider in a conventional ink jet recording apparatus. In FIG. 10, wipers 8 and 9 are mounted with the caps 1A and 1B on a slider 7, and the slider 7 is movable along slider cams 13a and 13b provided in a base portion 13 of an apparatus main body. Hence, the wipers 8 and 9 and caps 1A and 1B are also regulated for positions in a vertical direction by moving with the slider 7 along cam surfaces of the slider cams 13a and 13b, and are controlled so as to take a predetermined capping position, a predetermined wiping position, and the like. In addition, a lock lever 4 which fixes the slider by locking the slider with the base portion 13 at the time of wiping operation is provided in the slider 7.
FIG. 11 is a partial cutaway front view showing a state at the time when the slider 7 in FIG. 10 advances to the capping position of the recovery mechanism portion with following the motion of the carriage. FIG. 12 is a partial cutaway front view showing a state at the time when the carriage inversely moves toward a recording region to thereby hold the slider 7 in the wiping position. In FIG. 11, when a recording mechanism portion which is constructed of a recording head 5 and a carriage 6 advances to the recovery mechanism portion, a right-hand side face of the carriage 6 abuts on a bumping portion 7a of the slider 7. Protrusions (or shanks) 7b are provided in a total of four places of both side faces of the slider 7, and these protrusions are made to abut on cam faces of the slider cams 13a and 13b provided in the base portion 13 in an apparatus main body side.
When the carriage 6 abuts on the bumping portion 7a and advances further, the slider 7 moves along the slider cams 13a and 13b with interlocking with (following) the motion of the carriage, and rises gradually. Then, when the carriage 6 moves to the capping position in FIG. 11, the caps 1A and 1B are stuck to discharge port surfaces 51 of recording heads 5A and 5B, and generate a capping state of sealing the discharge ports. When the carriage further moves in an approach direction from the capping position, a hook portion 4b provided in an end portion of the lock lever 4 clears a lock lever cam 13c in the side toward an apparatus main body 13 to move to the right-hand side in the figure, and is locked by the lock lever cam.
The lock lever 4 is energized leftward in the figure by a tension spring (return spring) 4d attached to the base portion 13. A slider insertion portion 4c is provided in the lock lever 4, and one end portion, which is in the left-hand side in the figure, among four protrusions 7b of the slider 7 is inserted into the slider insertion portion. The slider 7 inversely moves toward the recording region and then the protrusion 7b abuts on a left-hand edge face of the slider insertion portion 4c. Hence, the slider 7 is held (locked or stopped) in the wiping position in FIG. 12.
When the recording mechanism portion further moves toward the recording region, the recording mechanism portion is separated from the stopped slider. The wipers 8 and 9, which are constructed of blade-like rubbery elastic bodies, are installed in an end portion of the slider in the edge part toward the recording region. In addition, in the above-mentioned wiping position, the slider 7 is stopped in a height position where respective wipers 8 and 9 advance (overlap) to the discharge port surfaces 51 of the recording heads 5A and 5B only by a preferable amount. Then, when the carriage 6 further moves toward the recording region, a discharge port surface of each recording head rubs with each wiper, and a wiping operation which wipes the discharge port surface is performed.
When wiping is finished and the recording mechanism portion further moves toward the recording region, a lock lever release portion (not shown) of the carriage 6 abuts on a carriage abutting portion 4a of the lock lever 4, and presses this. This lock lever release portion is constructed of a protrusion or a step portion and the like, which are formed in a right-hand end portion of the carriage 6 in the figure. And, its height position is selected in a position where (1) the lock lever release portion does not contact the carriage abutting portion 4a when the carriage advances, that is, when the slider 7 and the lock lever 4 become in lowest positions, and (2) it contacts the carriage abutting portion when the lock lever release portion is in the wiping position where the slider 7 and the lock lever 4 rise to some extent.
In this way, when the lock lever release portion (not shown) abuts on the carriage abutting portion 4a, the lock lever 4 rotates counterclockwise in the figure and centers the protrusion 7b inserted in the slider insertion portion 4c. Thereby, since the hook portion 4b leaves the lock lever cam 13c, locking of the slider is released. The unlocked slider is returned to the original wiper evacuating position (downward position) by a slider spring 15 attached to the base portion 13. According to the above structure, it is possible to perform the capping operation and wiping operation by making the slider perform the following motion along the cam faces using the motion of the carriage.
Nevertheless, in the above-mentioned ink jet recording apparatus, although the wiping position of the slider 7 is regulated by the lock lever 4, there were the following technical tasks in this conventional locking means by the lock lever. That is, the above-mentioned conventional locking means is constructed so as to make the lock lever cam 13c, formed in the inner portion of the recovery mechanism portion of the apparatus main body, lock the lock lever connected to the slider to perform positional regulation of the slider only in a carriage moving direction. For this reason, it is necessary for the slider cams 13a and 13b to provide horizontal portions 13f having length corresponding to carriage motion at the time of the wiping operation.
In addition, since the lock lever 4 is connected to only one of four protrusions (shanks) 7b of the slider, a posture of the slider is apt to become unstable. Then, in order to stabilize the posture of the slider, it is necessary to make the lock lever cam 13c lock the lock lever in the state where the four protrusions are located in the horizontal portions 13f. In this way, since the horizontal portions 13f were required for the slider cams 13a and 13b, total length of the slider cams became long and size of the apparatus main body in a width direction was large.
In addition, for proper wiping operation, it is required for an approach amount (overlap amount) of the wipers 8 and 9 to the discharge port surfaces of the recording head 5 to be suitable. However, in the above-mentioned conventional structure, there are many factors for determining the height position of the wipers, which include height of the lock lever cam 13c of the apparatus main body, height of the horizontal portions 13f of the slider cams 13a and 13b, geometry of the lock lever 4, positions of the four protrusions 7b of the slider, and the like. Therefore, since the approach amount of the wipers was influenced by manufacturing errors of these portions to be changed quite greatly, it was difficult to maintain the approach amount in a suitable amount. Thus, in order to stably secure the suitable approach amount, it has been demanded to greatly enhance manufacturing accuracy of each portion.